The present invention is related to compounds having pharmacological activity, to pharmaceutical compositions containing these compounds, and to a pharmaceutical method. More particularly, this invention concerns square-planar cis-platinum (II) four-coordinate complexes having anti-microbial activity as well as activity against the L1210 and P388 murine leukemia cell lines, to pharmaceutical compositions containing these complexes, and to methods of treating microbial infections and of inhibiting the growth of neoplasms in a mammal.